<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
</head>
<body>

</body>
</html>

<script>
	alert(-0.8/0);
	// alert(100+undefined);
	// alert(100+null)
	// alert(100+true);
	// alert(100+false);
</script>